The present invention relates generally to the determination of properties of a cooktop, and, more particularly, to a method and apparatus for method for determining properties of a cooktop by providing an ultrasound waveform to the cooktop surface and measuring a resultant ultrasound waveform.
In some conventional cooktops and ranges, standard porcelain enamel cooktop surfaces have been replaced by smooth, continuous-surface, high-resistivity cooktops located above one or more heating elements, such as electrical heating elements or gas burners. The smooth, continuous-surface cooktops are easier to clean because they do not have seams or recesses in which debris can accumulate. The continuous cooktop surface also prevents spillovers from coming into contact with the heating elements or burners.
Some conventional cooktops and/or ranges can detect properties of the cooktop, vessel or cooking process via devices that provide contact with a cooking vessel disposed on an electric heating element or on the cooking vessel support of a gas burner. Such contact-based systems, however, have not proven to be feasible for continuous-surface cooktops, and especially glass-ceramic cooktops due to the difficulties of placing contact sensors thereon. Cooking vessel contact sensors generally disrupt the continuous cooktop appearance, weaken the structural rigidity of the cooktop, and increase manufacturing costs. Also, such contact-based systems are not inherently reliable on smooth-surface cooktops because cooking vessel with warped or uneven bottoms may exert varying forces on the contact sensors and give a false contact indication.
In other conventional cooktops or ranges, the reflective properties of a cooking vessel positioned on the surface of the cooktop are used to determine properties of the cooktop, vessel or cooking process. However, the reflective properties vary between vessels. In addition, with age and usage of the vessel, the reflective properties of the vessel can diminish due to for example corrosion, staining and burned on coatings. Thus, the use of vessel reflective properties to determine the properties the cooktop, vessel or cooking process may, at times, be unreliable or inconsistent.
Therefore, it is desirable to provide a system that detects properties of the cooktop without compromising the structural integrity of the cooktop surface. In addition, it is also desirable to provide a system for detecting properties of a cooktop that is independent of cooking vessel composition, flatness of the bottom of the cooking vessel, or weight of the cooking vessel. Additionally, it is desired to have a cooktop and/or range that uses a system that detects properties of a cooktop independent of the reflective properties of the cooking vessel when determining properties of the cooktop, cooking vessel or cooking process.
In one representative embodiment, an apparatus for determining at least one property of a cooktop is provided. The cooktop includes a cooktop surface and a vessel selectively positioned on the cooktop surface. The apparatus comprises an ultrasound transducer contacting the cooktop surface. The ultrasound transducer includes an ultrasound transmitter that contacts the cooktop surface and provides an ultrasound waveform to the cooktop surface creating an excitation in the cooktop surface. The ultrasonic transducer also includes an ultrasound receiver contacting the cooktop surface. The ultrasound receiver receives a resultant ultrasound waveform in response to the excitation and produces a receiver output signal in response to the resultant ultrasound waveform. A processor is connected to the ultrasound transducer. The processor receives the receiver output signal and produces a processor output signal corresponding to the at least one property of the cooktop.
In another representative embodiment, an apparatus for determining at least one property of a cooktop is provided. The cooktop has a cooktop surface with a top and bottom and a vessel selectively positioned on the top of the cooktop surface. The apparatus includes an ultrasound transmitter that contacts the bottom of the cooktop surface at a first position. The ultrasonic transmitter transmits an ultrasound waveform within the cooktop surface creating an excitation in the cooktop surface. An ultrasound receiver also contacts the bottom of the cooktop surface at a second position, and the first position is different from the second position. The ultrasound receiver receives a resultant ultrasound waveform in response to the ultrasound waveform produced by the ultrasound transmitter, and the ultrasound receiver produces a receiver output signal based on the resultant ultrasound waveform. A processor is connected to the ultrasound receiver for receiving the receiver output signal. The processor produces a processor output signal in response to the receiver output signal, the processor output signal being indicative of the at least one property of the cooktop.
In even another representative embodiment, a method for determining at least one property of a cooktop is provided. The cooktop has a cooktop surface and a vessel selectively positioned on the cooktop surface. The method includes the steps of contacting a transducer to the cooktop surface. An ultrasound waveform is provided to the cooktop surface from a transmitter of the transducer. An excitation is created in the cooktop surface from the provided ultrasound waveform. A resultant ultrasound waveform is received using a receiver of the transducer. The resultant ultrasound waveform is in response to the excitation produced by the ultrasound waveform. A receiver output signal is produced in response to the resultant ultrasound waveform. A processor output signal is determined based on the receiver output. The processor output signal corresponds to the at least one property of the cooktop.